1. Technical Field
The present invention relates to a magnetoresistive effect magnetic head which reads signals recorded on a magnetic recording medium by using magnetoresistive effect. The present invention also relates to a rotary magnetic head apparatus using the magnetoresistive effect magnetic head and to a manufacturing method of this rotary magnetic head apparatus.
2. Prior Art
In recent years, recording densities are increasing in the field of magnetic recording. Instead of bulk heads, thin film heads are widely used as magnetic heads suited for high density recording. A thin film head is manufactured through the use of manufacturing techniques in the field of semiconductor integrated circuits, more specifically film formation techniques such as vaporization, sputtering, and the like, and photolithography techniques such as photoengraving, etching, and the like. These techniques make it possible to form a fine shape with high precision to mass-produce heads. Thin film heads having these advantages are currently mainstreamed as magnetic heads for high-density recording/reproducing systems such as hard disks, tape streamers, and the like.
Of these thin film heads, a magnetoresistive effect magnetic head (referred to hereafter as an MR head) is now in wide use as a magnetic reproducing head on hard disk drives and the like. The MR head reads signals using magnetoresistive effect.
A magnetoresistive effect element (referred to hereafter as an MR element) provides the magnetoresistive effect. The MR head comprises the MR element formed in a gap according to the thin film formation. The width of a thin film MR element determines the track width, easily providing narrow tracks. The MR head provides higher read sensitivity than a coil-type inductive head. Owing to no influence of inductance, the MR head can transfer signals at high-frequencies. The MR head is considered to be an essential device for high-density recording/reproducing systems in the future.
The following describes a configuration example of a magnetic head conventionally used for a hard disk drive with reference to FIGS. 1 through 3. A magnetic head 100 is formed as a so-called composite magnetic head comprising an MR head for reproduction and an inductive head for recording which are layered on each other. The magnetic head 100 is mounted on a floating slider 200 which floats above a magnetic disk. The magnetic head 100 is positioned so that a magnetic sensor is exposed from an air bearing surface (ABS) 201 of a floating slider 200 to a magnetic disk""s signal recording surface.
Specifically, the magnetic head 100 is provided with a substrate 102 made of Alxe2x80x94TiC and the like on which a base film 101 made of Al2O3 and the like is formed. On the substrate 102 where the base film 101 is formed, there is formed a soft magnetic film of Sendust and the like which functions as a lower magnetic shield thin film 103. A nonmagnetic nonconductive film 104 of Al2O3 and the like is formed on the substrate 102 where the lower magnetic shield thin film 103 is not formed. The nonmagnetic nonconductive film 104 is as thick as the lower magnetic shield thin film 103.
Another nonmagnetic nonconductive film of Al2O3 and the like is formed on the lower magnetic shield film 103 and the nonmagnetic nonconductive film 104 to function as a lower shield gap film 105. On the lower shield gap film 105, an SAL bias layer, an intermediate layer, and an MR layer are laminated to form an MR element 106. The MR element 106 is positioned at one side (a face against a medium) of the magnetic head 100 so that one end of the MR element 106 is exposed outward from the air bearing surface 201 of the floating slider 200.
On both ends of the MR element 106 in the track direction, there is formed a pair of ferromagnetic films 107 and 108 for making a magnetic domain for the MR element 106 to be single-domain and suppressing a Barkhausen noise. On the ferromagnetic films 107 and 108, there is formed a pair of resistance decreasing films 124 and 125 for decreasing resistance of the MR element 106 and a portion electrically connected to the MR element 106.
On the lower shield gap film 105, there is provided a pair of conductors 109 and 110 for supplying the MR element 106 with a sense current. One end of the conductors 109 and 110 is connected to a pair of ferromagnetic films 107 and 108. The pair of conductors 109 and 110 is electrically connected to the MR element 106 via the pair of ferromagnetic films 107 and 108.
On the other end of the pair of conductors 109 and 110, there are provided external connection terminals 111 and 112 which are connected to an external circuit. End faces of the external connection terminals 111 and 112 are exposed outward. Lead wires and the like are connected to these end faces.
On the lower shield gap film 105, there are formed the MR element 106, the ferromagnetic films 107 and 108, the conductors 109 and 110, and the like. In a manner which covers these elements, a nonmagnetic nonconductive film of Al2O3 and the like is also formed on the lower shield gap film 105 and functions as an upper shield gap film 113. On the upper shield gap film 113, a soft magnetic film of Permalloy and the like is formed and functions as an upper magnetic shield thin film 114.
The above-mentioned portions on the magnetic head 100 constitute an MR head for reproduction. The magnetic head 100 allows the soft magnetic film in the form of the upper magnetic shield thin film 114 to function as a lower-layer core for the inductive head for recording. Namely, the soft magnetic film of Permalloy and the like formed on the upper shield gap film 113 functions as an upper magnetic shield thin film for the MR head and as a lower-layer core for the inductive head.
The soft magnetic film functions as a lower-layer core for the inductive head. A nonmagnetic nonconductive film of Al2O3 and the like is formed on the soft magnetic film and is used as a recording gap film 115. On the recording gap film 115, a thin film coil 117 is formed at a position far away from a face against a medium so that the coil 117 is embedded in an insulating film 116. As shown in FIG. 1, the coil 117 is connected to a pair of conductors 118 and 119 and external connection terminals 120 and 121 through which a drive current is supplied.
A soft magnetic film of Permalloy and the like is formed on the recording gap film 115 from a position facing a medium to a position far away from that position. The soft magnetic film functions as an upper-layer core 122.
Namely, at the side facing a medium on the magnetic head 100, there is provided the recording gap film 115 sandwiched by the lower-layer core 114 and the upper-layer core 122 which face to each other. At a position far away from the side facing a medium, the coil 117 is provided between the lower-layer core 114 and the upper-layer core 122. The soft magnetic film functions as the upper-layer core 122 on the magnetic head 100. At a position farthest from the face against a medium, the upper-layer core 122 is connected to the soft magnetic film functioning as the lower-layer core 114.
The above-mentioned portions on the magnetic head 100 constitute an inductive head for recording. As the top layer on the magnetic head 100, there is formed a nonmagnetic nonconductive film of Al2O3 and the like functioning as a protection layer 123.
The magnetic head 100 according to the above-mentioned configuration is formed at the side of the floating slider 200 so that the face against the medium is positioned at the side of the air bearing surface 201 of the floating slider 200. When the floating slider 200 floats above a magnetic disk, the magnetic head 100 reads or writes signals onto the magnetic disk. At this time, part of the MR element 5 in the MR head as the magnetic sensor and part of the recording gap film 115 as the inductive head are positioned opposite to the signal recording surface of the magnetic disk.
Tape mass storage systems use magnetic tapes as recording media. Some tape mass storage systems employ a reproducing/recording technology called the helical scan technology. The helical scan technology comprises a fixed drum and a rotary drum which is rotatively mounted against the fixed drum. The helical scan technology records or reproduces signals on a magnetic tape by using a rotary magnetic head apparatus whose magnetic head is mounted on a rotary drum. The magnetic tape is helically wound on an external surface of the rotary magnetic head apparatus. As the rotary drum rotates, the magnetic head moves and slides touchingly across the magnetic tape for recording or reproducing signals on the magnetic tape.
According to the helical scan technology, the magnetic head touchingly slides across the running magnetic tape at a high speed for recording and reproducing signals. This provides a fast relative slide speed between the magnetic tape and the magnetic head, improving a data transfer rate.
In recent years, a technology is proposed to use an MR head as a reproducing head, narrow recording tracks, and record and reproduce signals at an increased recording density for tape mass storage systems according to the helical scan technology.
In tape mass storage systems according to the helical scan technology, the magnetic head touchingly slides across the magnetic tape at a high speed, making it necessary to implement countermeasures against abrasion of the magnetic head. FIGS. 4 and 5 show an MR head used as a reproducing head for a tape mass storage system according to the helical scan technology. The MR head is so structured that the MR element 106 and the like is sandwiched and protected by a pair of guard materials 131 and 132.
As a recording medium, the helical scan tape system uses a magnetic tape which is highly coercive and has a thicker magnetic recording layer than that of a magnetic disk. As a recording head, it is necessary to use a bulk-type magnetic head which uses a core material with a high saturation flux density. Accordingly, a reproducing MR head is configured as an independent head element separated from the recording head.
When the MR head is configured as an independent head element, there is a problem of difficulty in positioning when mounting the MR head on the rotary drum. When the MR head is used as a reproduction head in the helical scan tape system, the MR head needs to be accurately mounted on a head support plate by positioning so that the MR element 106 as the magnetic sensor is positioned optimally. It is also necessary to accurately mount the head support plate equipped with the MR head on the rotary drum by positioning so that the MR element 106 as the magnetic sensor is positioned optimally.
However, the MR element 106 is very thin, namely approximately 0.1 xcexcm. It is very difficult to directly recognize the MR element 106 using an image. With respect to the above-mentioned composite magnetic head 100 as shown in FIG. 2, the relatively thick upper-layer core 122 for the recording head is formed just above the MR element 106. The upper-layer core 122 can be used as a marker and serve as a reference for positioning. However, the MR head used as a reproducing head in the helical scan tape system is configured as an independent head element separated from the recording head. Unlike the composite magnetic head 100, it is impossible to use the upper-layer core 122 of the recording head as a marker.
For such an MR head, it is possible to consider using the lower magnetic shield thin film 103 or the upper magnetic shield thin film 114 as a marker. These films can be used as references for positioning. Namely, the lower magnetic shield thin film 103 or the upper magnetic shield thin film 114 is formed so that its center in the width direction matches the center of the MR element 106 in the width direction. It is possible to identify the center of the lower magnetic shield thin film 103 or the upper magnetic shield thin film 114 in the width direction to be the center of the MR element 106 in the width direction, namely the track center for accurate positioning.
As shown in FIG. 5, if a width W100 of the lower magnetic shield thin film 103 or a width W101 of the upper magnetic shield thin film 114 is too large on the MR head, however, it is impossible to simultaneously recognize both ends of the lower magnetic shield thin film 103 or the upper magnetic shield thin film 114 in the width direction with regard to a visual field for image recognition. In this case, it is necessary to identify the center of the lower magnetic shield thin film 103 or the upper magnetic shield thin film 114 in the width direction, namely the center of the MR element 106 in the width direction by measuring a distance from one end of the lower magnetic shield thin film 103 or the upper magnetic shield thin film 114 in the width direction. Such a measurement makes it difficult to accurately determine the center of the MR element 106 in the width direction and degrades positioning accuracy because of a tapered shape at the end of the lower magnetic shield thin film 103 or the upper magnetic shield thin film 114 in the width direction or because of a long distance to be measured.
The present invention has been made in consideration of the foregoing. It is therefore an object of the present invention to provide an MR head which is capable of improving the positioning precision for the head support plate and the rotary drum and is suitable for the helical scan technology as a reproduction head. It is another object of the present invention to provide a rotary magnetic head apparatus using such an MR head and a manufacturing method of the rotary magnetic head apparatus.
A magnetoresistive effect magnetic head according to the present invention forms an inter-shield gap between joint surfaces for a pair of guard materials through the intermediation of a pair of magnetic shield thin films. In this inter-shield gap, there are provided a magnetoresistive effect element and ferromagnetic films connected to both ends of the magnetoresistive effect element in the width direction. These magnetoresistive effect element and ferromagnetic films are partially exposed outward from a sliding surface against a magnetic recording medium. With respect to at least one of the pair of magnetic shield thin films, the width of the exposed portion is smaller than the sum of the width for a magnetoresistive effect element portion exposed from the sliding surface and the width for a ferromagnetic film portion exposed therefrom.
For a magnetoresistive effect magnetic head having the above-mentioned configuration according to the present invention, the magnetic shield thin film whose width is so determined as mentioned above can be effectively used as a marker for mounting the magnetoresistive effect magnetic head itself on a head support plate or a rotary drum.
With respect to this magnetoresistive effect magnetic head, the magnetic shield thin film is exposed from the media sliding surface for a width which is smaller than the sum of the width for a magnetoresistive effect element portion exposed from the sliding surface and the width for a ferromagnetic film portion exposed therefrom. The entire portion exposed from the sliding surface sufficiently fits into a visual field during image recognition. When mounting the magnetoresistive effect magnetic head on the head support plate or the rotary drum, it is possible to recognize the magnetic shield thin film portion exposed from the sliding surface as an image. Accurate positioning is available, for example, by measuring a distance from the end in the width direction to determine a position of the magnetoresistive effect element.
There may be the case where the magnetic shield thin film concenters on the magnetoresistive effect element in the width direction. Especially, in this case, it is possible to identify the center of the magnetic shield thin film in the width direction to be the center of the magnetoresistive effect element in the width direction, namely the track center for accurate positioning. At this time, it is also possible to recognize both ends of the magnetic shield thin film in the width direction exposed from the media sliding surface. Even if these ends are tapered, effects thereof can be nullified for properly measuring a distance. A distance to be measured is shortened, thus decreasing measurement errors for precision measurement and accurate positioning.
Another magnetoresistive effect magnetic head according to the present invention forms an inter-shield gap between joint surfaces for a pair of guard materials through the intermediation of a pair of magnetic shield thin films. In this inter-shield gap, there are provided a magnetoresistive effect element and ferromagnetic films connected to both ends of the magnetoresistive effect element in the width direction. These magnetoresistive effect element and ferromagnetic films are partially exposed outward from a sliding surface against a magnetic recording medium. A pair of notches is formed on at least one of the pair of magnetic shield thin films at its portion exposed from the sliding surface. A distance between these notches is smaller than the sum of the width for the magnetoresistive effect element portion exposed from the sliding surface and the width for the ferromagnetic film portion exposed therefrom.
For another magnetoresistive effect magnetic head having the above-mentioned configuration according to the present invention, a pair of notches is formed on the magnetic shield thin film at its portion which is exposed from the media sliding surface. The magnetic shield thin film can be effectively used as a marker for mounting the magnetoresistive effect magnetic head itself on a head support plate or a rotary drum.
As mentioned above, a pair of notches is formed at a portion where the magnetic shield thin film is exposed from the media sliding surface of the magnetoresistive effect magnetic head. A distance between these notches is smaller than the sum of the width for the magnetoresistive effect element portion exposed from the sliding surface and the width for the ferromagnetic film portion exposed therefrom. It is possible to sufficiently fit the entire portion between these notches into a visual field during image recognition. Accordingly, when mounting the magnetoresistive effect magnetic head on the head support plate or the rotary drum, it is possible to recognize the portion between the notches on the magnetic shield thin film as an image. Accurate positioning is available, for example, by measuring a distance from either notch to determine a position of the magnetoresistive effect element.
There may be the case where the center between the pair of notches matches the center of the magnetoresistive effect element in the width direction. Especially, in this case, it is possible to identify the center between these notches to be the center of the magnetoresistive effect element in the width direction, namely the track center for accurate positioning.
A rotary magnetic head apparatus according to the present invention comprises an apparatus body having a stationary drum and a rotary drum, and a magnetic reproducing head. The rotary drum is rotatively mounted against the fixed drum. The magnetic reproducing head is mounted at the rotary drum side of the body. On the rotary magnetic head apparatus, the magnetic reproducing head is provided with an inter-shield gap between joint surfaces of a pair of guard materials through the intermediation of a pair of magnetic shield thin films. In this inter-shield gap, there are provided a magnetoresistive effect element and ferromagnetic films connected to both ends of the magnetoresistive effect element in the width direction. These magnetoresistive effect element and ferromagnetic films are partially exposed outward from a sliding surface against a magnetic recording medium. With respect to at least one of the pair of magnetic shield thin films, the width of a portion thereof which is exposed from the sliding surface is smaller than the sum of the width for the magnetoresistive effect element portion exposed from the sliding surface and the width for the ferromagnetic film portion exposed therefrom.
A rotary magnetic head apparatus having the above-mentioned configuration according to the present invention is equipped with a magnetoresistive effect magnetic head as a magnetic reproducing head. The apparatus is applicable to a magnetic recording/reproducing system with high recording density. According to this rotary magnetic head apparatus, the magnetic reproducing head contains a magnetoresistive effect element. A magnetic shield thin film is narrower than the sum of the width for a magnetoresistive effect element portion exposed from the sliding surface and the width for a ferromagnetic film portion exposed therefrom. This magnetic shield thin film is used as a marker for accurately mounting the magnetic reproducing head on the rotary drum so that the magnetic reproducing head can appropriately read signals.
Another rotary magnetic head apparatus according to the present invention comprises an apparatus body having a stationary drum and a rotary drum, and a magnetic reproducing head. The rotary drum is rotatively mounted against the fixed drum. The magnetic reproducing head is mounted at the rotary drum side of the body. On the rotary magnetic head apparatus, the magnetic reproducing head is provided with an inter-shield gap between joint surfaces of a pair of guard materials through the intermediation of a pair of magnetic shield thin films. In this inter-shield gap, there are provided a magnetoresistive effect element and ferromagnetic films connected to both ends of the magnetoresistive effect element in the width direction. These magnetoresistive effect element and ferromagnetic films are partially exposed outward from a sliding surface against a magnetic recording medium. A pair of notches is formed on at least one of the pair of magnetic shield thin films at its portion exposed from the sliding surface. A distance between these notches is smaller than the sum of the width for the magnetoresistive effect element portion exposed from the sliding surface and the width for the ferromagnetic film portion exposed therefrom.
Another rotary magnetic head apparatus having the above-mentioned configuration according to the present invention is equipped with a magnetoresistive effect magnetic head as a magnetic reproducing head. The apparatus is applicable to a magnetic recording/reproducing system with high recording density. According to this rotary magnetic head apparatus, a pair of notches is formed on the magnetic shield thin film of the magnetic reproducing head. This magnetic shield thin film is used as a marker for accurately mounting the magnetic reproducing head on the rotary drum so that the magnetic reproducing head can appropriately read signals.
A manufacturing method for a rotary magnetic head according to the present invention relates to the manufacture of a rotary magnetic head apparatus which comprises an apparatus body having a stationary drum and a rotary drum, and a magnetic reproducing head. The rotary drum is rotatively mounted against the fixed drum. The magnetic reproducing head is mounted at the rotary drum side of the body. The magnetic reproducing head is provided with an inter-shield gap between joint surfaces of a pair of guard materials through the intermediation of a pair of magnetic shield thin films. In this inter-shield gap, there are provided a magnetoresistive effect element and ferromagnetic films connected to both ends of the magnetoresistive effect element in the width direction. These magnetoresistive effect element and ferromagnetic films are partially exposed outward from a sliding surface against a magnetic recording medium. With respect to at least one of the pair of magnetic shield thin films, the width of a portion thereof which is exposed from the sliding surface is smaller than the sum of the width for the magnetoresistive effect element portion exposed from the sliding surface and the width for the ferromagnetic film portion exposed therefrom. The manufacturing method is used for manufacturing such a magnetoresistive effect magnetic head having the above-mentioned configuration. The magnetic shield thin film is narrower than the sum of the width for the magnetoresistive effect element portion exposed from the sliding surface and the width for the ferromagnetic film portion exposed therefrom. The manufacturing method is characterized in that this magnetic shield thin film is used as a marker for mounting the magnetoresistive effect magnetic head on the rotary drum side of the body.
The manufacturing method for a rotary magnetic head apparatus according to the present invention makes it possible to accurately mount a magnetoresistive effect magnetic head as a magnetic reproducing head on a rotary drum.
Another manufacturing method for a rotary magnetic head apparatus according to the present invention relates to the manufacture of a rotary magnetic head apparatus which comprises an apparatus body having a stationary drum and a rotary drum, and a magnetic reproducing head. The rotary drum is rotatively mounted against the fixed drum. The magnetic reproducing head is mounted at the rotary drum side of the body. The magnetic reproducing head is provided with an inter-shield gap between joint surfaces of a pair of guard materials through the intermediation of a pair of magnetic shield thin films. In this inter-shield gap, there are provided a magnetoresistive effect element and ferromagnetic films connected to both ends of the magnetoresistive effect element in the width direction. These magnetoresistive effect element and ferromagnetic films are partially exposed outward from a sliding surface against a magnetic recording medium. A pair of notches is formed on at least one of the pair of magnetic shield thin films at its portion exposed from the sliding surface. A distance between these notches is smaller than the sum of the width for the magnetoresistive effect element portion exposed from the sliding surface and the width for the ferromagnetic film portion exposed therefrom. The manufacturing method is used for manufacturing such a magnetoresistive effect magnetic head having the above-mentioned configuration. The manufacturing method is characterized in that this magnetic shield thin film is used as a marker for mounting the magnetoresistive effect magnetic head on the rotary drum side of the body.
Another manufacturing method for a rotary magnetic head apparatus according to the present invention makes it possible to accurately mount a magnetoresistive effect magnetic head as a magnetic reproducing head on a rotary drum.
As mentioned above, the magnetoresistive effect magnetic head according to the present invention has the following feature. Namely, with respect to at least one of the pair of magnetic shield thin films, the width of a portion thereof which is exposed from the sliding surface is smaller than the sum of the width for the magnetoresistive effect element portion exposed from the sliding surface and the width for the ferromagnetic film portion exposed therefrom. The magnetic shield thin film portion exposed from the sliding surface can be effectively used as a marker for mounting the magnetoresistive effect magnetic head on a head support plate or a rotary drum with accurate positioning.
Another magnetoresistive effect magnetic head according to the present invention has the following feature. Namely, a pair of notches is formed on at least one of the pair of magnetic shield thin films at its portion exposed from the sliding surface. A distance between these notches is smaller than the sum of the width for the magnetoresistive effect element portion exposed from the sliding surface and the width for the ferromagnetic film portion exposed therefrom. The magnetic shield thin film positioned between the pair of notches can be effectively used as a marker for mounting the magnetoresistive effect magnetic head on a head support plate or a rotary drum with accurate positioning.
By having the above-mentioned magnetoresistive effect magnetic head as a magnetic reproducing head, the rotary magnetic head apparatus according to the present invention is applicable to a magnetic recording/reproducing system with high recording density. Additionally, since the magnetic reproducing head is accurately mounted on the rotary drum, the magnetic reproducing head can appropriately read signals.
The manufacturing method for a rotary magnetic head apparatus according to the present invention makes it possible to accurately mount the magnetoresistive effect magnetic head as a magnetic reproducing head on the rotary drum.